1. Field of the Invention
The present invention relates to an electrophotographic processor such as a printer, a photocopier, a facsimile machine using plain paper, etc and more particularly, to a paper feeding unit driving device for an electrophotographic processor that can drive a convey roller and a paper feeding roller with one solenoid.
2. Description of the Related Art
U.S. Pat. No. 4,529,188 to Sternick discloses a paper feeding unit driving device having one solenoid, a pair of spring-clutches, arms and a lever. The following description, including FIGS. 1-2B, concerns the operation of the apparatus of U.S. Pat. No. 4,529,188.
As shown in FIG. 1, the drive assembly includes gears 98 and 88 for providing positive drive capability from the main machine drive to both a feed roller shaft and a convey roller shaft. On one side of the gear 88 there are formed a convey roller 84 for providing a copy paper to an image forming unit and a shaft 86 for transmitting the positive drive capability of the gear 88 to the convey roller 84. A wrap spring 90 for controlling the rotation of the shaft 86 is provided on the other side of the gear 88, and exterior of the wrap spring is a collar 94 for connecting the gear 88 and a hub 96 to each other. The collar 94 is provided with a plurality of stops on its cylindrical surface for engagement with one end of a control actuator arm 110 to interrupt the rotational motion of the convey roller 84, and an output hub 96 connected to one side of the collar 94 is fixed to the shaft 86.
On one side of the gear 98 there are formed segmented feed rollers 80 for providing a copy paper contained in a paper cassette to the convey roller 84 and a shaft 82 for transmitting the positive drive capability of the gear 98 to the segmented feed rollers 80. A wrap spring 100 for controlling the rotation of the shaft 82 is provided on the other side of the gear 98, and exterior of the wrap spring is a collar 102 for connecting the gear 98 and a cam 108 to each other. The collar 102 is provided with a stop 104 on its inboard surface for engagement with the other end of control actuator arm 110 to interrupt the rotational motion of the convey roller 84, and has a stop 106 for engagement with the other end of control actuator arm 110 to interrupt the rotational motion of the segmented feed rollers 80. The cam 108 that comes into contact with a lever 112 to actuate the control actuator arm 110 upward and downward is provided on one side of the collar 102. The control actuator arm 110 and the cam 108 are connected to each other by a spring 114 to actuate by the retraction thereof. A hub that is provided on one side of the cam 108 is fixed to one end of the shaft 82. Under the gears 88 and 98, the control actuator arm 110 is formed to cut off the rotational motion of the segmented feed rollers 80. The lever 112 and the control actuator arm 110 are fixed to the frame by a control arm pivot 120. The lower section of the control actuator arm 110 is provided with solenoid 116 for actuating the control actuator arm 110 to transmit a drive to the segmented feed rollers 80 and the convey roller 84. A plunger 118 is formed on the solenoid 116 and connected to the end of the control actuator arm 110 to actuate the control actuator arm 110 upward and downward.
Referring to FIGS. 2A and 2B, the gear 88 is rotated counterclockwise by the drive of the main motor, and the gear 98 is rotated clockwise. When the solenoid 116 is energized, the segmented feed rollers 80 are driven in a direction to feed a copy paper through the nip. The cam 108 is rotated clockwise, and the stop 106 provided on one side of the cam 108 comes into contact with one end of the control actuator arm 110 to cut off the drive that is transmitted to the segmented feed rollers 80. The segmented feed rollers 80 then stop their rotation, and the convey roller 84 is energized to convey the paper to the image forming unit.
The cam 108 continues rotating to contact the stop 104 and one end of the control actuator arm 110. The lever 112, having one end which rides on the cam surface, comes into contact with the upper dead point of the cam 108, and simultaneously with this, the other end of the control actuator arm 110 is engaged with one of the stops 92 to cut off the drive that is transmitted to the convey roller 84. The lever 112 and the control actuator arm 110 are connected to each other by the spring 114 to actuate by the retraction thereof.
As the cam 108 keeps rotating, the lever 112 is placed on the upper dead point of the cam 108, and the other end of the control actuator arm 110 is engaged with one of the stops 92 of the collar 94. At the same time, the segmented feed rollers 80 are rotated in a direction to feed the paper to the convey roller 84. The solenoid 116 keeps its energized force until the control actuator arm 110 is engaged with one the stops 92.
The solenoid 116 keeps on being energized from the paper delivery of the segmented feed rollers 80 to the paper delivery of the convey roller 84 to the image forming unit, which may reduce the life of the solenoid 116. In addition, the long turned-on state of the solenoid 116 requires more energy, and the lever 112 and the control arm 110 become connected with each other by the spring 114 and control the mutual actuation to demand the precise action of the spring. The use of the lever 112 and the spring 114 causes an increase in the number of components and production cost, and makes the structure complex so as to have a disadvantageous yield.
The following additional patents have features in common with the present invention, but nevertheless do not teach or suggest the specifically recited arrangement of the present invention.
U.S. Pat. No. 4,516,764 to Tamura entitled Paper Feeding Device. PA1 U.S. Pat. No. 4,438,915 to Akamatsu, et al. entitled Sheet Feeding Device. PA1 U.S. Pat. No. 3,545,743 to Limberger entitled Apparatus for Drawing in Templates into a Processing Device, More particularly for Copying Machines and the Like. PA1 U.S. Pat. No. 3,294,019 to Taylor entitled Rotary Printing Machine. PA1 U.S. Pat. No. 3,100,111 to Elchorn, et al. entitled Sheet Feeding Machine. PA1 U.S. Pat. No. 3,137,495 to Elchorn entitled Sheeting Feeding Mechanism.